It is common knowledge that carpets which are cleaned regularly wear significantly longer than carpets permitted to carry traffic while soiled. Of course, regular cleaning additionally provides the advantage of improved appearance. Concerning the wear factors associated with the soiling of carpet, the particulate matter or dirt which develops within a carpet is abrasive in nature. Consequently, traffic over the dirty portions of a carpet tends to cause the abrasive matter to abraid the pile and backing thereof, thus shortening the effective lifespan of the material.
Inasmuch as carpeting now is used extensively in commercial applications as well as the home for purposes of background noise control as well as appearance, the square yardage of wall-to-wall carpet installation has assumed somewhat enormous proportions and has, concomitanly, led to demands for cleaning devices, the effectiveness of which extends beyond the capabilities of conventional domestic vacuum cleaners. Since it is impractical to remove carpeting for carrying out liquid based cleaning procedures, a veriety of somewhat portable devices have been proposed or introduced into the marketplace for providing in situ cleaning. Such devices, as may be exemplified in U.S. Pat. Nos. 4,019,218, 3,942,217; and 3,909,197, serve to discharge jets of pressurized cleaning solution into the pile, nap or weave of the carpet to be cleaned and, thereafter, apply suction to the nap for the purpose of withdrawing the dirt entraining cleaning solution (usually a water-detergent mixture) from the pile. Generally, the temperature of the liquid carrying the detergent is warm to hot, and in some devices, steam is developed for application to the carpet. Typical steam applicators are described, for example, in U.S. Pat. No. Re26,950. Application of liquid to the carpeting is carried out utilizing a handheld device conventionally referred to as a "wand". The head of this wand incorporates one or a plurality of nozzles for expelling detergent carrying liquid under pressure into the carpet as well as a suction arrangement which serves to rapidly remove the pressure-applied detergent-carrying liquid as well as entrained dirt particles. Such an arrangement is intended to avoid difficulties otherwise encountered in generating excessive moisture at the supporting strata of the carpet, i.e. mats or flooring positioned immediately beneath the carpet layer. Preferably, no significant amount of moisture remains in the carpet upon passing the wand implement thereover.
Depending upon the design, carpet cleaning devices of the high liquid pressure type under consideration, which currently are in the marketplace, evidence a variety of shortcomings both from the standpoint of their ability to treat the pile to an extent wherein a carpet surface of pleasant appearance results, as well as in the labor requirements encountered in their operation. For example, their utilization has been observed to require an excessive amount of physical exertion and to induce noticeable frustrations on the part of the operator thereof. This latter, labor intensifying aspect of the devices detracts from their profitability in that the square yardage of carpet cleaning capability of the devices becomes limited due to physical fatigue of the operator as well as in operational time lost in operator requirements for accommodating to the demands of the machine itself.
The difficulties encountered by operators in using current devices stem in part from the spatial structuring of components within the principal housings of the cleaning systems. Certain of the devices, for example as exemplified in U.S. Pat. No. 3,942,217, are more or less vertically structured to retain cleaning liquid tanks, an electric motor, liquid return receptors for the vacuum systems, pumps and blowers. Such vertical orientation requires the operator to fill the devices by lifting buckets of hot water to higher elevations to fill the detergent retaining tanks. When the devices subsequently are manipulated, for instance, down the hallway of an apartment building or along an office corridor, the heated water at such higher elevation tends to splash on the operator, thus frustrating performance efficiency. Further in this regard, where waste material return conduits and/or pressurized liquid conduits extend to the wand element from the forward end of such housings, manipulation of the entire cleaning paraphernalia becomes time consuming and difficult, inasmuch as the conduiting may extend for distances amounting to well over 100 feet. During the cleaning operation, the operator hand-manipulates the wand such as to pass it over the carpet in a reciprocatory fashion. Over a period of time, the operator's physical attitude or posture is one facing downwardly toward the carpet, a posture which becomes fatiguing over a period of use of the devices. Further in the above regard, while the devices or apparatus at hand may be considered somewhat portable, the power demands imposed upon their electrically powered motor or motors by water pumps and air blowers are significant. Inasmuch as only domestic-type power source outlets generally are available for operation of the machines, all too often overloading current demands are encountered by the operators causing the tripping of circuit breakers or blowing of fuses with a resultant operational down-time.
Now considering the cleaning performance of devices present in the marketplace, as noted above, the basis of their operation is to apply a generally hot water-born detergent or the like under relatively high pressure into the surface of the carpet. This material, now carrying dirt and abrasives from the carpet, is then supposed to be somewhat immediately picked up by the suction nozzle of the hand held wand of the apparatus. The resultant material is returned to a waste collection tank for ultimate disposal. While a significant amount of abrasive dirt and the like is removed in the course of this operation, a residue of the detergent material with entrained dirt particles does remain within the pile of the carpet following the cleaning procedure. Additionally, the procedure tends to build up the presence of a static charge within the carpet leading to undesirable surface effects. This static charge appears to cause an agglomerating effect in many carpet structures, again detracting from its appearance.
For certain carpet materials, for example, wool, the conventional suction devises utilized for water-detergent recovery, fail to remove an adequate amount of moisture following deposition thereof. In some instances, an interval of days may be required to fully dry the treated carpet, following which, as noted above, a residue of detergent is found to remain upon the carpet fibers.